George W. Crile.

Origin and Nature of Emotions online

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Miscellaneous Papers






IN response to numerous requests I have brought together into this volume
eight papers which may serve as a supplement to the volumes previously
published[*] and as a preface to monographs now in preparation.

[*] Surgical Shock, 1899; Surgery of the Respiratory System, 1899;
Problems Relating to Surgical Operations, 1901; Blood Pressure
in Surgery, 1903; Hemorrhage and Transfusion, 1909;
Anemia and Resuscitation, 1914; and Anoci-association, 1914
(with Dr. W. E. Lower).

In the first of these addresses, the Ether Day Address, delivered at
the Massachusetts General Hospital in October, 1910, I first
enunciated the Kinetic Theory of Shock, the key to which was found
in laboratory researches and in a study of Darwin's "Expression
of the Emotions in Man and in Animals," whereby the phylogenetic
origin of the emotions was made manifest and the pathologic
identity of surgical and emotional shock was established.
Since 1910 my associates and I have continued our researches through -
(a) Histologic studies of all the organs and tissues of the body;
(b) Estimation of the H-ion concentration of the blood in the emotions
of anger and fear and after the application of many other forms of stimuli;
(c) Functional tests of the adrenals, and (d) Clinical observations.

It would seem that if the striking changes produced by fear
and anger and by physical trauma in the master organ of the body -
the brain - were due to WORK, then we should expect to find
corresponding histologic changes in other organs of the body as well.
We therefore examined every organ and tissue of the bodies of animals
which had been subjected to intense fear and anger and to infection and
to the action of foreign proteins, some animals being killed immediately;
some several hours after the immediate effects of the stimuli had passed;
some after seances of strong emotion had been repeated several
times during a week or longer.

The examination of all the tissues and organs of these animals
showed changes in three organs only, and with few exceptions in all
three of these organs - the brain, the adrenals, and the liver.
The extent of these changes is well shown by the photomicrographs
which illustrate the paper on "The Kinetic System" which is included
in this volume. This paper describes many experiments which show
that the brain, the adrenal, and the liver play together constantly
and that no one of these organs - as far at least as is indicated
by the histologic studies - can act without the co-operation
of the other two.

Another striking fact which has been experimentally established
is that the deterioration of these three organs caused by emotion,
by exertion, and by other causes is largely counteracted,
if not exclusively, during sleep. If animals exhausted by the continued
application of a stimulus are allowed complete rest for a certain
number of hours, _*without sleep_, the characteristic histologic
appearance of exhaustion in the brain, adrenals, and liver is not
altered notably, whereas in animals allowed to sleep for the same
number of hours the histologic changes in these organs are lessened -
in some cases obliterated even.

This significant phenomenon and its relation will be dealt with in
a later monograph.

Many of the arguments and illustrations by which the primary
premises were established are repeated - a few in all - many in
more than one of these addresses. It will be observed, however,
that the APPLICATION of these premises varies, and that their
SIGNIFICANCE broadens progressively.

In the Ether Day Address the phylogenetic key supplied by Darwin was
utilized to formulate the principle that the organism reacts as a unit
to the stimuli of physical injury, of emotion, of infection, etc.
To the study of these reactions (transformations of energy)
the epoch-making work of Sherrington, "The Integrative Action
of the Nervous System," gave an added key by which the dominating
role of the brain was determined. Later the original work
of Cannon on the adrenal glands gave facts, and an experimental
method by which Darwin's phylogenetic theory of the emotions
was further elaborated in other papers, especially in the one
entitled "Phylogenetic Association in Relation to the Emotions,"
read before The American Philosophical Society in April, 1911.

PROBLEMS. . . . . . . . . . . . . . . . . . . . . . . . . . .1

55 PAIN, LAUGHTER, AND CRYING. . . . . . . . . . . . . . . . . 77


A MECHANISTIC VIEW OF PSYCHOLOGY . . . . . . . . . . . . . .127

A MECHANISTIC THEORY OF DISEASE. . . . . . . . . . . . . . .157

THE KINETIC SYSTEM . . . . . . . . . . . . . . . . . . . . .173


INDEX. . . . . . . . . . . . . . . . . . . . . . . . . . . .237


[*] Address delivered at the Massachusetts General Hospital on
the sixty-fourth anniversary of Ether Day, Oct. 15, 1910.

The discovery of the anesthetic properties of ether and its practical
application to surgery must always stand as one of the great
achievements of medicine. It is eminently fitting that the anniversary
of that notable day, when the possibilities of ether were first
made known to the world, should be celebrated within these walls,
and whatever the topic of your Ether Day orator, he must fittingly
pause first to pay tribute to that great event and to the master
surgeons of the Massachusetts General Hospital. On this occasion,
on behalf of the dumb animals as well as on behalf of suffering humanity,
I express a deep sense of gratitude for the blessings of anesthesia.

Two years ago, an historic appreciation of the discovery of ether
was presented here by Professor Welch, and last year an address
on medical research was given by President Eliot. I, therefore,
will not attempt a general address, but will invite your
attention to an experimental and clinical study. In presenting
the summaries of the large amount of data in these researches,
I acknowledge with gratitude the great assistance rendered by
my associates, Dr. D. H. Dolley, Dr. H. G. Sloan, Dr. J. B. Austin,
and Dr. M. L. Menten.[*]

[*] From the H. K. Cushing Laboratory of Experimental Medicine,
Western Reserve University, Cleveland.

The scope of this paper may be explained by a concrete example.
When a barefoot boy steps on a sharp stone there is an immediate discharge
of nervous energy in his effort to escape from the wounding stone.
This is not a voluntary act. It is not due to his own personal experience -
his ontogeny - but is due to the experience of his progenitors
during the vast periods of time required for the evolution
of the species to which he belongs, _i. e_., his phylogeny.
The wounding stone made an impression upon the nerve receptors
in the foot similar to the innumerable injuries which gave origin
to this nerve mechanism itself during the boy's vast phylogenetic or
ancestral experience. The stone supplied the phylogenetic association,
and the appropriate discharge of nervous energy automatically followed.
If the sole of the foot be repeatedly bruised or crushed by a stone,
shock may be produced; if the stone be only lightly applied,
then the consequent sensation of tickling causes a discharge of
nervous energy. In like manner there have been implanted in the body
other mechanisms of ancestral or phylogenetic origin whose purpose
is the discharge of nervous energy for the good of the individual.
In this paper I shall discuss the origin and mode of action of some
of these mechanisms and their relation to certain phases of anesthesia.

The word anesthesia - meaning WITHOUT FEELING - describes accurately
the effect of ether in anesthetic dosage. Although no pain
is felt in operations under inhalation anesthesia, the _*nerve
impulses excited by a surgical operation still reach the brain_.
We know that not every portion of the brain is fully anesthetized,
since surgical anesthesia does not kill. The question then is:
What effect has trauma under surgical anesthesia upon the part
of the brain THAT REMAINS AWAKE? If, in surgical anesthesia,
the traumatic impulses cause an excitation of the wide-awake cells,
are the remainder of the cells of the brain, despite anesthesia,
affected in any way? If so, they are prevented by the anesthesia from
expressing that influence in conscious perception or in muscular action.
Whether the ANESTHETIZED cells are influenced or not must be determined
by noting the physiologic functions of the body after anesthesia has
worn off, and in animals by an examination of the brain-cells as well.
It has long been known that the vasomotor, the cardiac, and the respiratory
centers discharge energy in response to traumatic stimuli applied
to various sensitive regions of the body during surgical anesthesia.
If the trauma be sufficient, exhaustion of the entire brain
will be observed after the effect of the anesthesia has worn off;
that is to say, despite the complete paralysis of voluntary
motion and the loss of consciousness due to ether, the traumatic
impulses that are known to reach the AWAKE centers in the medulla
also reach and influence every other part of the brain.
Whether or not the consequent functional depression and the morphologic
alterations seen in the brain-cells may be due to the low blood-pressure
which follows excessive trauma is shown by the following experiments:
The circulation of animals was first rendered STATIC by over-transfusion,
and was controlled by a continuous blood-pressure record on a drum,
the factor of anemia being thereby wholly excluded during the application
of the trauma and during the removal of a specimen of brain tissue
for histologic study. In each instance, morphologic changes
in the cells of all parts of the brain were found, but it required
much more trauma to produce brain-cell changes in animals whose
blood-pressure was kept at the normal level than in the animals
whose blood-pressure was allowed to take a downward course.
In the cortex and in the cerebellum, the changes in the brain-cells
were in every instance more marked than in the medulla.

There is also strong NEGATIVE evidence that traumatic impulses
are not excluded by ether anesthesia from the part of the brain
that is apparently asleep. This evidence is as follows:
If the factor of fear be excluded, and if in addition the traumatic
impulses be prevented from reaching the brain by cocain[*] blocking,
then, despite the intensity or the duration of the trauma within
the zone so blocked, there follows no exhaustion after the effect
of the anesthetic disappears, and no morphologic changes are noted
in the brain-cells.

[*] Since the presentation of this paper, novocain has been
substituted for cocain in operations under anoci-association.

Still further negative evidence that inhalation anesthesia offers
little or no protection to the brain-cells against trauma is derived
from the following experiment: A dog whose spinal cord had been
divided at the level of the first dorsal segment, and which had
then been kept in good condition for two months, showed a recovery
of the spinal reflexes, such as the scratch reflex, etc. Such an
animal is known as a "spinal dog." Now, in this animal, the abdomen
and hind extremities had no direct nerve connection with the brain.
In this dog, continuous severe trauma of the abdominal viscera and of
the hind extremities lasting for four hours was accompanied
by but slight change in either the circulation or in the respiration,
and by no microscopic alteration of the brain-cells (Fig. 1). Judging
from a large number of experiments on NORMAL dogs under ether,
such an amount of trauma would have caused not only complete
physiologic exhaustion of the brain, but also morphologic alterations
of all of the brain-cells and the physical destruction of many
(Fig. 2). We must, therefore, conclude that, although ether anesthesia
against exhaustion from the trauma of surgical operations; ether is,
so to speak, but a veneer. Under nitrous oxid anesthesia there is
approximately only one-fourth as much exhaustion as is produced by equal
trauma under ether (Fig. 3). We must conclude, therefore, either that
nitrous oxid protects the brain-cells against trauma or that ether
predisposes the brain-cells to exhaustion as a result of trauma.
With these premises let us now inquire into the cause of this
exhaustion of the brain-cells.

The Cause of the Exhaustion of the Brain-cells as a Result of Trauma
of Various Parts of the Body under Inhalation Anesthesia

Numerous experiments on animals to determine the effect of ether
anesthesia _per se_, _i. e_., ether anesthesia without trauma,
showed that, although certain changes were produced, these included
neither the physiologic exhaustion nor the alterations in the
brain-cells which are characteristic of the effects of trauma.
On turning to the study of trauma, we at once found in the behavior
of individuals as a whole under deep and under light anesthesia
the clue to the cause of the discharge of energy, of the consequent
physiologic exhaustion, and of the morphologic changes in the brain-cells.

If, in the course of abdominal operations, rough manipulations
of the parietal peritoneum be made, there will be frequently
observed a marked increase in the respiratory rate and an increase
in the expiratory force which may be marked by the production
of an audible expiratory groan. Under light ether anesthesia,
severe manipulations of the peritoneum often cause such vigorous
contractions of the abdominal muscles that the operator is greatly
hindered in his work.

Among the unconscious responses to trauma under ether anesthesia
are purposeless moving, the withdrawal of the injured part, and,
if the anesthesia be sufficiently light and the trauma sufficiently
strong, there may be an effort toward escape from the injury.
In injury under ether anesthesia every grade of response may be seen,
from the slightest change in the respiration or in the blood-pressure
to a vigorous defensive struggle. As to the purpose of these
subconscious movements in response to injury, there can be no doubt -

Picture what would be the result of a formidable abdominal operation
extending over a period of half an hour or more on an unanesthetized
human patient, during which extensive adhesions had been broken up,
or a large tumor dislodged from its bed! In such a case,
would not the nervous system discharge its energy to the utmost
in efforts to escape from the injury, and would not the patient suffer
complete exhaustion? If the traumata under inhalation anesthesia
are sufficiently strong and are repeated in sufficient numbers,
the brain-cells are finally deprived of their dischargeable nervous
energy and become exhausted just as exhaustion follows such strenuous
and prolonged muscular exertion as is seen in endurance tests.
Whether the energy of the brain be discharged by injury under anesthesia
or by ordinary muscular exertion, identical morphologic changes are
seen in the nerve-cells. In shock from injury (Fig. 2), in exhaustion
from overwork (Hodge and Dolley) (Fig. 4), and in exhaustion from pure fear
(Fig. 5), the resultant general functional weakness is similar -
in each case a certain length of time is required to effect recovery,
and in each there are morphologic changes in the brain-cells. It
is quite clear that in each of these cases the altered function
and form of the brain-cells are due to an _*excessive discharge
of nervous energy_. This brings us to the next question:
What determines the discharge of energy as a result of trauma
with or without inhalation anesthesia?

The Cause of the Discharge of Nervous Energy as a Result of Trauma
under Inhalation Anesthesia and under Normal Conditions

I looked into this problem from many viewpoints and there seemed
to be no solution until it occurred to me to seek the explanation
in certain of the postulates which make up the doctrine of evolution.
I realize fully the difficulty and the danger in attempting
to reach the generalization which I shall make later and in
the hypothesis I shall propose, for there is, of course, no direct
final proof of the truth of even the doctrine of evolution.
It is idle to consider any experimental research into the cause
of phenomena that have developed by natural selection during
millions of years. Nature herself has made the experiments on
a world-wide scale and the data are before us for interpretation.
Darwin could do no more than to collect all available facts and then
to frame the hypothesis by which the facts were best harmonized.
Sherrington, that masterly physiologist, in his volume entitled
"The Integrative Action of the Nervous System," shows clearly how
the central nervous system was built up in the process of evolution.
Sherrington has made free use of Darwin's doctrine in explaining
physiologic functions, just as anatomists have extensively
utilized it in the explanation of the genesis of anatomic forms.
I shall assume, therefore, that the discharge of nervous energy is
accomplished by the application of the laws of inheritance and association,
and I conclude that this hypothesis will explain many clinical phenomena.
I shall now present such evidence in favor of this hypothesis as time
and my limitations will admit, after which I shall point out certain
clinical facts that may be explained by this hypothesis.

According to the doctrine of evolution, every function owes
its origin to natural selection in the struggle for existence.
In the lower and simpler forms of animal life, indeed, in our
human progenitors as well, existence depended principally upon
the success with which three great purposes were achieved:
(1) Self-defense against or escape from enemies; (2) the acquisition
of food; and (3) procreation; and these were virtually the only purposes
for which nervous energy was discharged. In its last analysis,
in a biologic sense, this statement holds true of man today.
Disregarding for the present the expenditure of energy for procuring
food and for procreation, let us consider the discharge of energy
for self-preservation. The mechanisms for self-defense which we
now possess were developed in the course of vast periods of time
through innumerable intermediary stages from those possessed by
the lowest forms of life. One would suppose, therefore, that we must
now be in possession of mechanisms which still discharge energy on
adequate stimulation, but which are not suited to our present needs.
We shall point out some examples of such unnecessary mechanisms.
As Sherrington has stated, our skin, in which are implanted many
receptors for receiving specific stimuli which are transmitted
to the brain, is interposed between ourselves and the environment
in which we are immersed. When these stimuli reach the brain,
there is a specific response, principally in the form of
muscular action. Now, each receptor can be adequately stimulated
only by the particular factor or factors in the environment
which created the necessity for the existence of that receptor.
Thus there have arisen receptors for touch, for temperature,
for pain, etc. The receptors for pain have been designated _nociceptors_
(nocuous or harmful) by Sherrington.

On the basis of natural selection, nociceptors could have developed
in only those regions of the body which have been exposed to injury
during long periods of time. On this ground the finger, because it
is exposed, should have many nociceptors, while the brain, though the
most important organ of the body, should have no nociceptors because,
during a vast period of time, it has been protected by a skull.
Realizing that this point is a crucial one, Dr. Sloan and I made a series
of careful experiments. The cerebral hemispheres of dogs were exposed
by removing the skull and dura under ether and local anesthesia.
Then various portions of the hemispheres were slowly but
completely destroyed by rubbing them with pieces of gauze.
In some instances a hemisphere was destroyed by burning.
In no case was there more than a slight response of the centers governing
circulation and respiration, and no morphologic change was noted
in an histologic study of the brain-cells of the uninjured hemisphere.
The experiment was as completely negative as were the experiments
on the "spinal dog." Clinically I have confirmed these experimental
findings when I have explored the brains of conscious patients
with a probe to determine the presence of brain tumors.
Such explorations elicited neither pain nor any evidence of altered
physiologic functions. The brain, therefore, contains no mechanism -
no nociceptors - the direct stimulation of which can cause
a discharge of nervous energy in a self-defensive action.
That is to say, direct injury of the brain can cause no purposeful
nerve-muscular action, while direct injury of the finger does cause
purposeful nerve-muscular action. In like manner, the deeper portions
of the spinal region have been sheltered from trauma and they, too,
show but little power of causing a discharge of nervous energy
on receiving trauma. The various tissues and organs of the body
are differently endowed with injury receptors - the nociceptors
of Sherrington. The abdomen and chest when traumatized stand first
in their facility for causing the discharge of nervous energy, _i.
e_., THEY STAND FIRST IN SHOCK PRODUCTION. Then follow the extremities,
the neck, and the back. It is an interesting fact also that different
types of trauma elicit different responses as far as the consequent
discharge of energy is concerned.

Because it is such a commonplace observation, one scarcely realizes
the importance of the fact that clean-cut wounds inflicted
by a razor-like knife cause the least reaction, while a tearing,
crushing trauma causes the greatest response. It is a suggestive fact
that the greatest shock is produced by any technic which imitates
the methods of attack and of slaughter used by the carnivora.
_*In the course of evolution, injuries thus produced may well have
been the predominating type of traumata to which our progenitors
were subjected_. In one particular respect there is an analogy between
the response to trauma of some parts of the body of the individuals
of a species susceptible to shock and the response to trauma of the
individuals in certain other great divisions of the animal kingdom.
Natural selection has protected the crustaceans against their
enemies by protective armor, _e. g_., the turtle and the armadillo;
to the birds, it has given sharp eyes and wings, as, for instance,
the wild goose to another species - the skunk - it has given a noisome odor
for its protection. The turtle, protected by its armor against trauma,
is in a very similar position to that of the sheltered brain
of man and, like the brain, the turtle does not respond to trauma
by an especially active self-protective nerve-muscular response,
but merely withdraws its head and legs within the armored protection.
It is proverbially difficult to exhaust or to kill this animal by trauma.
The brain and other phylogenetically sheltered parts likewise give no
exhausting self-protective nerve-muscular response to trauma. The skunk
is quite effectively protected from violence by its peculiar odor.
This is indicated not only by the protective value of the odor itself,
but also by the fact that the skunk has no efficient nerve-muscular
mechanism for escape or defense; it can neither run fast nor can it
climb a tree. Moreover, in encounters it shows no fear and backs
rather than runs. The armadillo rolls itself into a ball for defense.
On these premises we should conclude that the turtle,
the armadillo, and the skunk have fewer nociceptors than has
a dog or man, and that they would show less response to trauma.

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